Clinical evaluation of Alfaxan-CD® as an intravenous anaesthetic in young cats

Objective   To describe and evaluate the use of Alfaxan-CD ® as an intravenous anaesthetic in young cats.
Design   Thirty-five Domestic Short-hair cats aged from 3 to 12 months were admitted into the University Veterinary Teaching Hospital-Sydney for elective surgery. Anaesthesia was induced with Alfaxan-CD® and maintained with isoflurane: 22 cats received no premedication and 13 cats received acepromazine (0.03 mg/kg) and butorphanol (0.3 mg/kg) subcutaneously 30 min prior to induction.
Qualitative and quantitative data for induction and recovery were recorded. Physiological parameters were recorded at 0, 2 and 5 min post induction, and every 5 min thereafter until the end of the procedure.
Results   Intravenous injection of Alfaxan-CD® resulted in rapid induction of anaesthesia with a mean time to intubation of 122 s. The mean dose of Alfaxan-CD® used was 4.2 mg/kg in unpremedicated cats and 2.7 mg/kg in premedicated cats. All cats maintained a heart rate above 95 beats/min. No cat developed hypoxaemia. Hypercapnoea was detected in 4 cats and hypotension was observed in 18 cats. Time to extubation ranged from 1 to 9 min. The mean time to sternal recumbency for premedicated cats was 11 min; 77% of premedicated cats and 23% of unpremedicated cats had a recovery score of 1 or 2.
Conclusion   Alfaxan-CD® is an effective anaesthetic agent in young healthy cats, providing a smooth induction and rapid recovery. Cats that were premedicated with acepromazine and butorphanol prior to induction with Alfaxan-CD® had better recovery scores than those that were not premedicated.     

Clinical evaluation of the anaesthetic sparing effect of brachial plexus block in cats

ObjectiveTo evaluate the isoflurane sparing effect and the post-surgical analgesia provided by a brachial plexus block (BPB) in cats undergoing distal thoracic limb surgery.Study designProspective randomized blinded clinical study.AnimalsTwenty client-owned cats.MethodsCats were assigned to receive either no BPB (group NB) or a nerve stimulator guided BPB (group BPB) using lidocaine (3.6 mg kg^?1) and bupivacaine (1.2 mg kg^?1). Pre-medication consisted of midazolam and ketamine intravenously (IV). Anaesthesia was induced with propofol IV to effect and maintained with isoflurane delivered in oxygen and a continuous rate infusion of fentanyl (2 μg kg^?1 hour^?1). End-tidal isoflurane concentration (Fe′ISO) was adjusted every 3 minutes guided by changes in cardiorespiratory parameters and reflexes present, to maintain a stable depth of anaesthesia. Five time points were chosen to record all parameters and compare values between groups. Recovery and post-operative pain assessment were performed using a visual analogue scale (VAS) at 15 and 45 minutes after extubation and thereafter at hourly intervals until 5 hours after placement of the BPB.ResultsNo clinically significant differences were seen for heart rate, respiratory rate and non-invasive blood pressure between groups. Mean Fe′ISO was significantly lower in group BPB compared with group NB at all time points. In group NB, all intraoperative measurements of Fe′ISO were significantly higher compared with baseline (3 minutes before start of surgery) measurements. During recovery, VAS scores for group BPB were significantly lower than for group NB. Additional analgesics were needed in all cats within the study period.Conclusion and Clinical relevanceIn cats undergoing orthopaedic surgery of the thoracic limb, BPB reduced intra-operative isoflurane requirement and pain during the early post-operative period when compared with procedures without a BPB. BPB is a useful adjunct to anaesthesia in such cases.     

Clinical evaluation of propofol as an intravenous anaesthetic agent in cats and dogs

The clinical efficacy and safety of an emulsion containing 10 mg/ml of the intravenous anaesthetic propofol were evaluated in cats and dogs by veterinary surgeons in eight practices in the United Kingdom. A total of 290 dogs and 207 cats were anaesthetised with propofol either as a single injection for procedures of short duration, or as an induction agent with maintenance provided by further incremental injections or as an induction agent with maintenance by gaseous agents. The mean induction doses of propofol for unpremedicated dogs and cats were respectively 6.55 mg/kg and 8.03 mg/kg. The mean induction doses after premedication with a tranquilliser were 4.5 mg/kg and 5.97 mg/kg for dogs and cats, respectively. Mean recovery times ranged, depending on the method of anaesthesia, from 23 to 40 minutes in dogs and from 27 to 38 minutes in cats; recovery was defined as the time at which the animals were alert and able to stand. Adverse side effects were infrequent, apnoea during induction being the commonest. Acepromazine and atropine were most often used as premedicants although in a few cases diazepam, xylazine and other agents were employed. No clinical incompatibility was observed between propofol and any of the other agents administered during the study. The rapid and usually excitement-free recovery of the animals was a valuable feature of anaesthesia with propofol.     

A clinical comparison of CT1341, ketamine, and xylazine in cats.

The new anesthetic agent CT1341 was compared to ketamine and xylazine in experimental and clinical situations with cats. Anesthesia with CT1341 was characterized by fast recovery times, good muscle relaxation, eyelid closure, occasional vomition, defecation, or urination during induction and recovery, generally smooth induction, and occasional hyperreflexive recoveries with much sneezing. The agent was moderately hypotensive, but caused little change in heart rate, central venous pressure, arterial pH, or blood gases.     

Clinical evaluation of R 51163, a new sedative in cattle

R 51163, a purine alkyl piperidine derivative, has been shown to produce reliable sedation in cattle of varying age and breed in three different types of experiments: transport and regrouping of cattle which had only been handled occasionally; manipulations and minor interventions; minor and major surgery with or without supplementary local anaesthesia. With dose rates of R 51163 at 0.05 mg/kg i.v. and of 0.10-0.15 mg/kg i.m. sedation became prominent within 10-15 min and lasted at least 60 min. Caesarean sections were performed under adequate sedation with R 51163 with dose ranging from 0.018 to 0.05 mg/kg i.v. and from 0.075 to 0.10 mg/kg i.m. The data suggest possible increased responsiveness to the drug at the time of calving.     

Assessment of methadone as an anaesthetic premedicant in cats

Ninety cats scheduled to undergo surgical procedures requiring the provision of postoperative analgesia were premedicated with either 0·1, 0·3 or 0·5 mgl/kg of racemic methadone by intramuscular injection. Each cat was assessed on three behavioural criteria before administration and again 20 minutes later. In a further 20 cats a specific assessment was made of the respiratory rate, heart rate and intraoperative minute volume during ovariohysterectomy following premedication with methadone (0·5 mgl/kg intramuscularly). In these cats an assessment of duration of analgesia was attempted. There was no significant change in behavioural scores following premedication with methadone. No cat vomited or became excited. No evidence of serious respiratory depression was found in the 20 cats monitored in detail. Duration of analgesia in cats receiving methadone (0·5 mgl/kg intramuscularly) before ovariohysterectomy varied from 1·5 to over 6·5 hours. Methadone may be used at dose rates of up to 0·5 mg/kg as a premedicant for cats without significant risk of undesirable behavioural changes or serious intraoperative respiratory depression when combined with the anaesthetic protocol described.     

Clinical evaluation of medetomidine, a novel sedative and analgesic drug for dogs and cats

Medetomidine, a potent alpha 2-adrenoceptor agonist, was investigated in open, multicenter clinical trials with patients of various canine and feline breeds (1736 dogs and 678 cats). The purpose of the study was to find an optimal dose of medetomidine for sedation and analgesia in clinical practice and to study how well the intended procedure could be performed under the influence of the drug. The mean dose (i.m.) of medetomidine used for examinations, clinical procedures and minor surgical interventions was 40 micrograms/kg, and for radiography 30 micrograms/kg. In cats the dose was 80-110 micrograms/kg. On the doses chosen, almost all animals were recumbent and 72% of the dogs and 85% of the cats were in a slight anaesthetic stage, unable to rise. The evaluation of the overall suitability of medetomidine (% of cases) in different indications was "very satisfactory" or "satisfactory" in 95% of dogs and 81-96% of cats. Side effects reported were limited almost exclusively to vomiting and muscle jerking in dogs (12% and 0.5% of the cases) and to vomiting in cats (65%). Medetomidine seems to suffice for pharmacological restraint of dogs and cats. The concomitant use of medetomidine (80-100 micrograms/kg) and ketamine (7 mg/kg) in cats (n = 295) provided a good anaesthesia (20-40 min). The recovery was smooth. The present study shows that medetomidine provides an effective level of sedation and analgesia for clinical use.     

Clinical evaluation of a cryptococcal antigen latex agglutination test for diagnosis of cryptococcosis in cats

A commercial cryptococcal antigen latex agglutination test was used to evaluate sera from 20 cats with cryptococcosis and 184 cats without cryptococcosis. Cryptococcal antigen was detected in the sera from 19 of 20 cats with cryptococcosis. Antigen was not detected in sera from any of the cats without cryptococcosis. The test had sensitivity of 95% and specificity of 100%.     

Clinical evaluation of cats with lower urinary tract disease.

In a prospective study, 141 cats with hematuria, dysuria, urethral obstruction, or combinations of these signs were evaluated by contemporary diagnostic methods and compared with 26 clinically normal cats (controls). Specific diagnosis was established in 45% (64/141) of cats affected with lower urinary tract disease (LUTD). Crystalline matrix plug-induced urethral obstruction was diagnosed in 21% (30/141) of affected cats, uroliths were identified in 21% (30/141) of affected cats, uroliths with concomitant bacterial urinary tract infection (UTI) were identified in less than 2% (2/141) of affected cats, and bacterial UTI alone was identified in less than 2% (2/141) of cats with LUTD. Viruses, mycoplasmas, and ureaplasmas were not isolated from urine samples collected from affected or control cats. Bovine herpesvirus 4 (BHV-4)-neutralizing antibodies were not detected in any serum sample obtained from cats with LUTD or from control cats. In contrast, BHV-4 antibodies were detected by an indirect immunofluorescent antibody (IFA) test in sera obtained from 31% (44/141) of cats with LUTD and 23% (6/26) of control cats. The prevalence of positive BHV-4 IFA test results in affected cats was not significantly different from that observed in control cats. Significant association was not apparent between positive BHV-4 IFA test results and clinical diagnosis, abnormal laboratory findings, or cat age. However, the number of male cats with BHV-4 IFA titer was significantly (P less than 0.02, chi 2 test) greater than that of female cats. Detection of BHV-4 antibodies in approximately 30% of affected and control cats indicates prior virus exposure. Further investigations are warranted to clarify the specific role of BHV-4 in cats with naturally acquired LUTD.     

Impact of preanaesthetic echocardiography on the planned anaesthetic management of cats

ObjectiveTo assess the impact of preanaesthetic echocardiography on the subsequent intended anaesthetic management plan in cats with incidental clinical findings that may indicate cardiac disease.Study designClinical study involving cats undergoing echocardiography and subsequent anaesthesia.AnimalsA total of 40 client-owned cats.MethodsEchocardiography was performed in conscious cats and the information was used to plan anaesthesia or sedation. An information sheet including relevant history, temperament, body condition score, clinical examination findings, current medication and results of any relevant tests such as haematology, biochemistry or Doppler blood pressure measurement was sent to three specialist anaesthetists and virtual case management plans were designed for each cat in two steps: step 1) anaesthetists were unaware of echocardiography results; and step 2) anaesthetists were aware of echocardiography results. In the second step the anaesthetists documented any changes to their original management plan, as either ‘step-up’ or ‘step-down’.ResultsOf the 40 cats, 26 had murmurs, four had a gallop rhythm, four had both findings and six had other findings. Pathology of potential haemodynamic significance was found on echocardiography in 23 cats, 17 of which anaesthetists had correctly identified as having disease before echocardiography. A proportion of cats with murmurs were subsequently deemed to have no significant pathology after echocardiography. Echocardiography findings in these cases were: dynamic left ventricular outflow tract obstruction (DLVOTO) without hypertrophy; DLVOTO without hypertrophy + dynamic right ventricular outflow tract obstruction (DRVOTO); DRVOTO; valvular dysplasia; normal. In a median of 26/40 (range 16–38) of cases, the anaesthetic plan was changed after provision of further information; in 15/40 (8–20) cases, this was a ‘step-up’ in care and in eight/40 (6–23) it was a ‘step-down’ in care. In cases with atrial enlargement (left atrium to aortic ratio of >1.6) and deemed at risk of cardiac failure, alpha-2 agonist use changed considerably with availability of echocardiography findings.Conclusionand clinical relevance Where there are abnormal cardiac findings on clinical examination in cats, echocardiography is required to accurately assess anaesthetic risk . The availability of echocardiographic information positively influences anaesthetic management.     

Kinetic evaluation of normal walking and jumping in cats, using a pressure-sensitive walkway

The kinetic parameters of the limbs of 23 normal, client-owned cats were evaluated by encouraging them to walk and jump normally on a pressure-sensitive walkway. Each cat was encouraged to walk across the walkway five times over a period of 30 to 45 minutes (by using food, toys, the owner's presence and a purpose-built tunnel) at a target speed of 0.6 m/s (and an acceleration of less than +/- 0.1 m/s(2)). They were then encouraged to jump on to the walkway from a height of 1 m five times at five-minute intervals. The kinetic parameters of peak vertical force (PVF) and vertical impulse (VI) were measured for each limb (the forelimbs only for the jumps), and expressed as a percentage of bodyweight (PVF(%BW) and VI(%BW/S)). Fifteen of the 23 cats satisfactorily completed three to five walks and two to five jumps that could be analysed. There were no significant differences between the PVF or VI of the left and right limbs, but both parameters were significantly greater for the forelimbs than the hindlimbs (P<0.001) for the walking data. The mean (sd) PVF(%BW) for the forelimbs and hindlimbs were 48.2 (6.0) and 38.3 (4.0), respectively, and the mean VI(%BW/s) were 16.9 (3.2) and 13.3 (2.8). Jumping down generated significantly greater PVF (P<0.01) and slightly greater VI than during walking; there were no significant differences between the left and right forelimbs. The mean PVF(%BW) was 148.9 (16.4) and the mean VI(%BW/s) was 18.1 (4.3).